在您的代码中，您有以下内容..........

in your code where you have the following..........

protected void drpLType_SelectedIndexChanged(object sender, EventArgs e)
{
    if (drpLType.SelectedValue == "Professional")
    {
        rdoMeapSupport.Enabled = true;
    }

    if (drpLType.SelectedValue == "Enterprise")
    {
        rdoMeapSupport.SelectedValue = null;
        rdoMeapSupport.Enabled = true;
    }

    if ((drpLType.SelectedValue == "Maintanence") || (drpLType.SelectedValue == "Reporting"))
    {
        rdoMeapSupport.Enabled = false;
        rdoMeapSupport.ClearSelection();
    }

}

不应该...... ...........

Shouldnt that be.............

protected void drpLType_SelectedIndexChanged(object sender, EventArgs e)
{
    if (drpLType.SelectedValue == "1")
    {
        rdoMeapSupport.Enabled = true;
    }

    if (drpLType.SelectedValue == "2")
    {
        rdoMeapSupport.SelectedValue = null;
        rdoMeapSupport.Enabled = true;
    }

    if ((drpLType.SelectedValue == "3") || (drpLType.SelectedValue == "4"))
    {
        rdoMeapSupport.Enabled = false;
        rdoMeapSupport.ClearSelection();
    }

}

原因是你有明确定义的VALUE =1值=2等

The reason for this is you have CLEARLY defined VALUE="1" value="2" etc